MSP430G2553: Waterproof Capsenes Design using MSP430FR2512

Hi Rajesh,

For Q1 :

Look like this design that place an LED inside the Capsense pad in normal, I do not think there are some problem. You can refer to EVM430-CAPMINI:
https://www.ti.com/tool/EVM430-CAPMINI

For Q2:

In your description, there is a 4cm gap between the product shell and the touch pad, and the mutual inductance method is adopted.

We suggest that you can use the FPC circuit board to make the touch part on the shell, this method will be better.

Best Regards

Johnson

Hello johnson,

Thanks for your quick response.

For Q1 :

Look like this design that places an LED inside the Capsense pad in normal, I do not think there is some problem. You can refer to EVM430-CAPMINI:

Rajesh-->>  we can place LED in same side of PCB inside PAD. Is this impact our cap sense functionality in design?

For Q2:

In your description, there is a 4cm gap between the product shell and the touch pad, and the mutual inductance method is adopted.

We suggest that you can use the FPC circuit board to make the touch part on the shell, this method will be better.

Rajesh-->> basically we need liquid tolerance for droplet and continuous stream. Can you please suggest which technology(self or mutual)  is best for our application?

our main requirement

1) Liquid tolerance for a continuous stream

2) LED inside Capsense PAD in the same size 

3) only one cap sense  button(on/off) switch is required

4) for 4mm Gape which technology is used to connect the PCB PAD  and enclosure. 

we are waiting for your reply ASAP.

Hi Rajesh,

For Q1 : 

1) Liquid tolerance for a continuous stream

You need use mutual technical in order to get better liquid tolerance for a continuous stream.

For Q2 : 

2) LED inside Capsense PAD in the same size 

The same size? Why do you need such a big LED? In the layout, the LED pad is placed on the opposite layer of the touch pad, which has little effect on the touch.

For Q4:

4) for 4mm Gape which technology is used to connect the PCB PAD  and enclosure. 

For the self-induction mode, we have tried using spring to extend the height of the touch pad.

But in the mutual inductance, we have no corresponding test data using two springs. We are recommend using FPC circuit and design the touch pad directly on the shell. Like this:

Best Regards

Johnson

Hello Johnson,

Thanks for your quick reply.

By mistake, I have written same size.

Q2) LED inside Capsense PAD on the same side 

Q4) for 4mm Gape which technology is used to connect the PCB PAD  and enclosure. 

For the self-induction mode, we have tried using spring to extend the height of the touchpad.

But in the mutual inductance, we have no corresponding test data using two springs. We recommend using FPC circuit and design the touchpad directly on the shell. Like this:

Rajesh-->> thanks for the suggestion but this is not suitable in mechanical. please suggest any other option.

Q5) Is Self-capacitance technology useful in Liquid tolerance for a continuous stream? please suugest.

we are waiting for your reply ASAP

Hello Johnson,

Thanks for your quick reply.

By mistake, I have written same size.

Q2) LED inside Capsense PAD on the same side 

Q4) for 4mm Gape which technology is used to connect the PCB PAD  and enclosure. 

For the self-induction mode, we have tried using spring to extend the height of the touchpad.

But in the mutual inductance, we have no corresponding test data using two springs. We recommend using FPC circuit and design the touchpad directly on the shell. Like this:

Rajesh-->> thanks for the suggestion but this is not suitable in mechanical. please suggest any other option.

Q5) Is Self-capacitance technology useful in Liquid tolerance for a continuous stream? please suugest.

we are waiting for your reply ASAP

Hi Rajesh,

Self-induction technology only supports waterproof touch, that is, there are water drops on the Touch pad.

For tolerance flow of liquid, self-induction technology is ineffective.

Best Regards

Johnson

HI Johnson,

Thanks for your reply.

Below are  my queries 

1) If Mutual capacitance technology is used and we have 4mm space between PCB and mechanical enclosure. our main problem is to use LED inside the cap sense pad on the same side.if we use the flex PCB and stick with enclosure then LED hight Problem in mechenical enclosure. Please suggest any other way.

Hi Rajesh,

Sorry, I am not very clear about your question.
You mean that if you use flex PCB to connect 4mm space and mechanical enclosure, then you can’t solder LED lights on flex PCB?

Best Regards

Johnson